A novel design and initial prototype of a blood pump used for extracorporeal circulation is presented. Due to the unique design, the pump has important desirable properties not found in current drivers, the standard roller and the centrifugal pumps. These properties include inherent pressure regulation without need for electronic detectors (i.e., will not over-pressurize or generate hazardous negative pressure), minimal blood damage, dependence of flow on natural supply, inability to pump air, and efficient energy conversion. Continuous, accurate monitoring of flow based on differential pressure measurement is included in the system. The objective is to further research the pump system and to develop the safest and least hemolytic blood driver used in applications of extracorporeal circulation, including cardiopulmonary bypass, blood oxygenation or CO2 removal, hemodialysis, blood filtration, and other therapeutic applications. The initial experimental procedure will involve the in-vitro evaluation of the pump's performance characteristics based on pressure regulation qualities, and on the effects of size and materials. The research to be performed will lead to the determination of the optimal design for each application. The pump will be compared to the standard roller and centrifugal pumps with regards to hemolysis, pressure safety properties, durability, and energy conversion efficiency.